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In-vitro activity of RP 59500, a new semisynthetic injectable pristinamycin against staphylococci

C von Eiff1, G Peters

  • 1Institute of Medical Microbiology, Westfälische Wilhelms-Universität Münster, Germany.

Zentralblatt Fur Bakteriologie : International Journal of Medical Microbiology
|April 1, 1996
PubMed

Insights

RP 59500, a novel streptogramin antibiotic, demonstrates potent in vitro antistaphylococcal activity comparable to vancomycin. It effectively inhibits both methicillin-susceptible and resistant strains of Staphylococcus aureus and coagulase-negative staphylococci.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Staphylococcal infections pose a significant threat, with increasing resistance to existing antibiotics.
  • Methicillin-resistant Staphylococcus aureus (MRSA) presents a particular challenge in clinical settings.
  • Novel antimicrobial agents are crucial for combating resistant bacterial strains.

Purpose of the Study:

  • To evaluate the in vitro efficacy of RP 59500, a new streptogramin, against staphylococci.
  • To compare the activity of RP 59500 with vancomycin and ciprofloxacin.
  • To assess the impact of methicillin resistance on the activity of these agents.

Main Methods:

  • Agar dilution method was employed for antimicrobial susceptibility testing.
  • A panel of 130 Staphylococcus aureus and 117 coagulase-negative staphylococci strains were tested.
  • Minimum inhibitory concentrations (MICs) were determined for RP 59500, vancomycin, and ciprofloxacin.

Main Results:

  • RP 59500 exhibited potent antistaphylococcal activity, with MICs ≤ 2 µg/mL for all tested strains.
  • The activity of RP 59500 was comparable to vancomycin against both S. aureus and coagulase-negative staphylococci.
  • RP 59500 and vancomycin maintained their efficacy regardless of methicillin resistance phenotype, unlike ciprofloxacin.

Conclusions:

  • RP 59500 is a promising new streptogramin with broad-spectrum activity against staphylococci, including resistant strains.
  • Its efficacy is not compromised by methicillin resistance, positioning it as a potential alternative to vancomycin.
  • Further clinical investigation of RP 59500 is warranted for treating staphylococcal infections.

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